1. Field of the Invention
The present invention relates to a loop antenna used for a portable compact receiver and an antenna holder therefor, and more particularly to a loop antenna having an antenna holder capable of installing and holding a subsidiary substrate with a capacitor mounted thereon.
2. Description of the Related Art
A portable compact receiver, particularly an individual selective calling receiver such as a pager, is normally carried by a user, so that the overall apparatus is made compact, a loop antenna which can be incorporated in the receiver is used as an antenna of that receiver, and an antenna holder is widely used as a holder for holding the loop antenna.
A conventional loop antenna is arranged such that, as its circuit diagram is shown in FIG. 4(a), a closed loop is formed by loop antenna elements 19 and 20 which equivalently function as inductance, a capacitor 4 inserted in such a manner as to divide the loop antenna into the loop antenna elements 19 and 20, and an impedance-matching dividing element 3 for tuning the antenna and establishing matching with a high-frequency circuit side. As its schematic diagram is shown in FIG. 4(b), the loop antenna elements 19 and 20 are fixedly held by an antenna holder 6, and the capacitor 4 and the impedance-matching dividing element 3 are mounted on a substrate 8 and are soldered to the loop antenna elements 19 and 20 at lands provided on the substrate 8.
With the above-described conventional loop antenna, there has been a problem in that it is impossible to obtain an intrinsic effective gain of the antenna due to the portion of loss resistance at the soldered portions of the capacitor 4 and the loop antenna elements 19 and 20 on the substrate 8.
In addition, individual selective calling receivers in recent years are increasingly becoming compact, and it is difficult to secure a mounting area. If the conventional antenna holder 6 is used, since the capacitor 4 is disposed on the substrate 8, the capacitor 4 must be soldered to the antenna elements 19 and 20 on the substrate 8, so that a large mounting space has been required.